Corsair and SuperTalent DDR3

Test Setup

Memory speeds tested:

Corsair
• PC3-1333MHz (low latency - 5-5-5-15-1T) 3GHz/9x333MHz FSB;
  
• PC3-1800MHz (stock latency - 7-7-7-20-1T) 3.15GHz/7x450MHz FSB;
  
• PC3-1800MHz (maximum overclock- 7-6-6-18-1T) 3.15GHz/7x450MHz FSB;
  
• PC3-1866MHz (maximum overclock- 8-8-8-24-1T) 3.27GHz/7x467MHz FSB;
  
  Super Talent
  
• PC3-1333MHz (low latency - 5-5-5-15-1T) 3GHz/9x333MHz FSB;
  
• PC3-1868MHz (stock latency and maximum overclock - 8-8-8-24-1T) 3.27GHz/7x467MHz FSB.

Corsair has stated on its forums that at 1,800MHz, given a good board and BIOS you should be able to run 7-6-6-20 without a voltage increase, however to make the sticks more reliable Corsair chose to only spec them at 7-7-7-20. We decided to test this and found that you could indeed run a super low latency of just 7-6-6-18-1T, but only at a massive 2.1V. Our maximum overclock of the Corsair modules also made it to the same speeds as the Super Talent memory but at a touch more voltage (2.12V).

Because the front side bus (FSB) operates as a four times multiplier of the actual FSB MHz value, 466MHz = 1,864MHz and 467MHz = 1,868MHz so exactly 1,866MHz for the Super Talent memory was unavailable. In addition, we had to increase the voltage to 2.1V instead of the rated 2.0V to keep it stable. The absolute fastest we could set the memory was 8-8-8-23-1T and the same FSB speed, which offers a completely unnoticeable performance improvement over 8-8-8-24-1T.

The maximum supported memory speed of X38 is officially 1,333MHz, so Asus has included separate 1,800MHz profiles that automatically overclock the CPU FSB to 450MHz while maxing out the available memory divider. Obviously not every CPU or setup will allow for 450MHz FSB and it doesn't automatically increase the voltage - so you have to make sure you adjust that yourself. Below, you can find our BIOS settings with the Asus P5E3 Deluxe (WiFi-AP parts disabled, the board and BIOS are otherwise essentially the same) and how CPU-Z sees it.

This inevitably means that the CPU speed varied and, even though we tried to keep it as close to the native 3GHz of an E6850 as possible, the extra MHz won't allow directly comparative results. However, this is the limit of what's available and there are no half multipliers available just yet.